The objective of this project is to study in depth the parameters which influence the adsorption of some prominent periodontal disease-associated bacteria to hydroxyapitite surfaces or epithelial cells under conditions which mimic the in vivo situation. Physical, chemical and environmental factors which may influence bacterial adsorption to surfaces will be investigated. The Langmuir adsorption model will be applied so that the comparative affinities and number of adsorption sites for the various strains can be obtained. The nature of the "salivary receptor macromolecules" involved in the adherent interaction will be investigated. Particular emphasis will be placed on identification of cell surface "receptor molecules" which interact with salivary components of epithelial cell surface receptors. Information on bacterial adsorption and bacterial cell "receptor molecules" will be used in studies to follow these to attempt to develop practical means for preventing initial infection by periodontopathic bacteria in rodents and therefore lead to application for prevention of human periodontal disease.